Tag Archives: Miniature Schnauzer

Hypersensitivity Skin Disorders

Clinical hypersensitivity disorders have been classified by Gel and Coombes. The following description is simplified since in many instances complex interactions occur simultaneously. Type 1 (immediate, anaphylactic) genetically susceptible individuals inhale (absorb percutaneously?) allergens such as pollen and house dust, and produce immunoglobulin E (IgE), which fixes to tissue mast cells and blood basophils the allergen subsequently comes into contact with its specific IgE, leading to the release of vasoactive amines, which cause tissue damage examples are urticaria, angio-oedema, atopy, drug eruption and flea-bite hypersensitivity Type 2 (cytotoxic) IgG or IgM with or without complement binds to complete antigens on body tissues the antigen—antibody reaction causes cell lysis examples are pemphigus, pemphigoid, cold agglutinin disease and dnig eruption Type 3 (immune complex) circulating antigen-antibody complexes fix complement and are deposited in blood vessel walls these complexes attract neutrophils; proteolytic and hydrolytic enzymes released from the neutrophils produce tissue damage examples are systemic lupus erythematosus and bacterial hypersensitivity Type 4 (delayed) incomplete Read more […]

Congenital and Hereditary Disorders of the Kidney

Structural Anomalies of the Kidney RENAL AGENESIS Renal agenesis is the complete absence of one or both kidneys. Bilateral renal agenesis is fatal and is a cause of early death in puppies and kittens (). Unilateral renal agenesis is more frequendy observed in puppies and kittens than is bilateral agenesis (). Unilateral renal agenesis may affect either kidney and is usually accompanied by ipsilateral ureteral agenesis. The etiopathogenesis of renal agenesis in dogs and cats is uncertain. A familial predisposition for renal agenesis in beagles, Shetland sheepdogs, and Doberman pinschers supports a genetic basis for the anomaly (Table 17-1). Unilateral renal agenesis may remain clinically silent, provided the contralateral kidney undergoes sufficient compensatory change to maintain normal hemostasis. Clinical findings may include an inability to palpate both kidneys or to detect a kidney by ultrasonography or contrast urography. Because of close associations in the development of the urogenital system, findings of abnormal or absent vas deferens, epididymal tails, or uterine horns at the time of castration or ovariohysterectomy should arouse suspicion of concurrent unilateral renal agenesis. Because unilateral renal Read more […]

Hypothyroidism

the commonest endocrine disorder of the dog the acquired naturally occurring condition has not been documented in the cat although the extremely rare congenital form has been described the metabolically active thyroid hormones are L-thyroxine (T4) and L-3,5,3-triiodothyronine (T3) Aetiology Primary congenital agenesis (rare) non-functional thyroid tumour (rare) lymphocytic thyroiditis; the most important cause (approximately 90%), an autoimmune disorder which results in thyroid destruction idiopathic thyroid necrosis and atrophy may represent the end stage of lymphocytic thyroiditis Secondary Less common than primary1 causes (less than 5%) TSH deficiency leading to inadequate stimulation of the thyroid gland with subsequent reduction in the production of thyroid hormone congenital hypopituitarism (usually in association with GH deficiency) pituitary neoplasia (may present with other signs, e.g. diabetes insipidus) Tertiary thyrotropin-releasing hormone (TRH) deficiency results in deficiency of TSH and reduction in thyroid hormone production due to hypothalamic lesions — extremely rare other equally rare causes of hypothyroidism include: iodine deficiency defects in thyroid Read more […]

The Globe And Orbit

Congenital Abnormalities Microphthalmos. Failure of the eye to develop to normal size is referred to as microphthalmos. Complete absence of the eye (anophthalmos) is extremely unusual in puppies and kittens. Microphthalmos is characterized by varying degrees of enophthalmos, with or without other ocular defects. Microphthalmos with multiple colobomas is an autosomal recessive trait linked to coat color in the Australian shepherd. In addition to small globes, affected dogs may have persistent pupillary membranes, cataract, equatorial staphylomas, choroidal hypoplasia, retinal dysplasia and detachment, and optic nerve hypoplasia. Vision is frequently impaired. Other breeds in which multiple ocular defects have been associated with coat color include the Great Dane, collie, Shetland sheepdog, and dachshund. Microphthalmos is also associated with inherited congenital cataracts in the miniature schnauzer, Old English sheepdog, Akita, and King Charles Cavalier spaniel. Microphthalmos occurs with retinal dysplasia in Bedlington terriers, Sealyham terriers, beagles, Labrador retrievers, and Doberman pinschers. Administration of griseofulvin to pregnant cats may produce microphthalmos in their offspring. Atypical Eye Position. Read more […]

The Lens and Vitreous

The lens develops rapidly in the early stages of embryogenesis, during which time it is nourished by the hyaloid vessel. The fully developed lens is avascular; by the second week of life, no remnants of the hyaloid system should remain. The normal lens often exhibits minor imperfections that can be easily detected with magnification in dogs and cats younger than 1 year. These include prominent anterior and posterior Y sutures and minute granules in its nucleus and cortex. A mosaic of brown pigment spots is occasionally seen on the anterior lens capsule near the center of the pupil, representing remnants of embryonic mesoderm. Disease of the vitreous would be expected to influence the lens or retina because of its attachments at the posterior lens surface and the optic disc. Congenital Abnormalities Congenital lens abnormalities include alterations in size or shape. Congenital absence of the lens (aphakia) is uncommon. In microphakia, the margin of the abnormally small lens along with elongated ciliary processes may be observed after pupillary dilation. Microphakia occurs along with other ocular defects in the Saint Bernard and beagle and in cats. Luxation of the microphakic lens may cause glaucoma. Lenticonus is a Read more […]

The Retina and Optic Nerve

Tapetal coloration of the fundus of the puppy and kitten is usually gray or blue at 6 to 8 weeks of age, gradually acquiring its adult coloration by 4 to 7 months of age when the tapetum matures. Myelination of the optic disc may also be incomplete in the puppy and kitten, giving the impression of a small, well-defined nerve head that takes on a more fluffy appearance as adult myelination occurs.Both congenital and acquired disorders of the retina and optic nerve are recognized in the young dog and cat. These may be inherited, as with collie eye anomaly, or secondary to postnatal influences, as occurs with canine distemper-induced retinitis. Congenital abnormalities can be diagnosed as early as 6 weeks of age, when the posterior segment is clearly observed. The more common congenital abnormalities of the canine fundus are summarized in Table Congenital Abnormalities of the Canine Fundus. Acquired abnormalities develop with advancing age and in this discussion are limited to those in dogs and cats younger than 6 months of age. Table Congenital Abnormalities of the Canine Fundus (diagnosed as early as 6-8 wk of age). DISORDER BREED CHARACTERISTIC FEATURES Collie eye anomaly Collie, Shetland sheepdog, Read more […]

Pancreatitis

Inflammatory disease of the human pancreas is usually divided into acute and chronic types based on a combination of clinical and pathological criteria, this classification may be loosely applied to cats and dogs (). • Acute pancreatitis refers to inflammation of the pancreas with a sudden onset and little or no permanent pathological change after recovery. • Chronic pancreatitis is a continuing inflammatory disease characterized by irreversible morphological change (fibrosis and atrophy) and it possibly leads to permanent impairment of function. Both acute and chronic pancreatitis may be further subdivided based on the aetiology, if known, and the severity. Complications of both types of pancreatitis may include: • Fluid accumulations around the inflamed pancreas • Pseudocyst (a collection of sterile pancreatic juice enclosed by fibrous or granulation tissue) • Localized necrosis • Pancreatic abscess (a circumscribed collection of pus, usually in proximity to the pancreas, containing little or no pancreatic necrosis). • Infected necrosis (from which bacteria can be cultured — very rare). Classification based on aetiology is desirable, but this is rarely possible. When Read more […]

The Eye As An Optical Device

A primary function of the eye is to form a crisply focused image on the retina. The optical components through which light travels to reach the retina are the cornea, aqueous humor, lens, and vitreous body. For proper image formation these components must remain transparent and maintain precise relationships to one another. One of the exciting areas of ongoing research is attempting to define the mechanisms whereby these relationships are maintained during growth of the eye. A point source of light located at the visual horizon emits rays that are convergent, divergent, and parallel relative to the eye. At a great distance only rays that are essentially parallel will enter the pupil of the dog. Divergent and convergent rays will pass peripheral to the pupillary aperture. If the eye is focused at infinity (is emmetropic), parallel rays will be refracted and imaged as a point on the dog’s retina. If the dog’s eye is ametropic (either myopic or hyperopic), the rays will not be properly imaged on the retina and will form a blurred circle. As an object is brought closer and closer to the dog’s eye, the percentage of divergent rays entering the pupil will increase, requiring an increase in refractive power of the Read more […]

Paraparesis: Vascular diseases

Fibrocartilaginous embolic myelopathy Clinical signs: Neuroanatomical localization often is associated with the spinal cord intumescences but other spinal cord regions can be involved (). Thoracolumbar signs are more common than cervicothoracic. Clinical signs usually are associated with trauma or exercise. Asymmetrical lesion distribution () is a clinical feature due to the distribution of the blood vessels to the spinal cord parenchyma (); however, the lesion can be symmetrical. Symmetrical lesions more often are associated with loss of nociception. Spinal hyper-aesthesia can be present initially but is absent afterthe onset of ischaemia. Maximal neurological deficits usually occur within the first 24 hours. Dogs with lumbosacral intumescent involvement more often have loss of deep pain perception. Pathogenesis: FCE is characterized by acute spinal cord infarction caused by embolism of fibrocartilage identical to that of the nucleus pulposus of the intervertebral disc (). Many theories exist as to the pathophysiology for embolization (). Entry of disc material into the vascular system and embolization from the point of entry to the arteries and veins of the spinal cord has yet to be elucidated. Non-chohdrodystrophoid Read more […]

Tetraparesis: Vascular diseases

Spinal haemorrhage Clinical signs: The clinical signs reflect the side of the haemorrhage and are acute in onset. They can be multifocal. Pathogenesis: Bleeding disorders can be inherited (e.g. von Willebrand’s disease) or acquired secondary to rodenticide toxicity or infectious / inflammatory diseases (e.g. immune-mediated thrombocytopenia, disseminated intravascular coagulation). Indeed, tick-borne infectious causes of vasculitis and thrombocytopenia, such as Rocky Mountain spotted fever, are common in some parts of the world. Haemorrhage into the CNS can occur with any bleeding disorder and, although unusual, it can be the first manifestation of the disease. For example, epidural haemorrhage causing spinal cord compression has been reported in Dobermann Pinschers with von Willebrand’s disease (). The presence of petechiae, ecchymoses or prolonged bleeding following venipuncture should alert the veterinarian to the possibility of a bleeding disorder. It is not unusual to find extensive extradural haemorrhage at the site of acute intervertebral disc herniations or vertebral fractures and luxations. These animals do not have an underlying coagulopathy; the haemorrhage has occurred as a direct result of disruption Read more […]